We found the cause of that bug! If the restart button is pressed more that once before the next scene is fully loaded, the scene will try to load multiple times. As a result, it gets caught on that loading screen.
Unfortunately, if this happens, the game will need to be closed out. Due to Game Jam restrictions, a fix for this bug cannot be uploaded yet. To avoid this for the time being, please be careful to only select restart once.
Thank you again for playing!